JPS6381613A - Magnetic head - Google Patents

Abstract

PURPOSE:To permit easy production by forming a 1st Co-Zr alloy layer having high saturation magnetic flux density and contg. Zr at a low ratio on one of the butt surfaces in a gap part, Then forming a 2nd Co-Zr alloy layer having low saturation magnetic flux density and contg. Zr at the ratio higher than in the 1st layer thereon. CONSTITUTION:The magnetic Co-Zr alloy layers 11 contg. Zr at a low ratio are formed on the surfaces in the gap part of a yoke 10 consisting of Mn-Zn single crystal ferrite and the magnetic Co-Zr alloy layers 2 contg. Zr at the higher ratio are formed thereon. An SiO2 gap material is used for the gap part 13. These magnetic layers are formed by an RF magnetron sputtering method. The magnetic layers 12 of low saturation magnetic flux density to change the effective gap are formed on the Co-Zr alloy contg. Zr at the higher ratio and the magnetic layers 11 of high saturation magnetic flux density are formed of the Co-Zr alloy contg. Zr at the lower ratio, therefore, these layers are easily producible by a sputtering method necessitating mere changing-over of targets. Since the magnetic permeabilities of the two magnetic layers exhibit nearly the same high values, the magnetic head having good characteristics is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a magnetic head, and more particularly to the structure of a gap portion of a magnetic head.

(Prior Art) Currently, in magnetic recording and reproducing devices, dual-purpose magnetic heads for recording and reproducing are widely used in order to reduce production costs and simplify the device.

The gap length of a magnetic head should be large during recording from the standpoint of recording efficiency, but during playback it should be small so that short wavelength signals can be sufficiently reproduced.Therefore, the gap length of a dual-purpose magnetic recording head is To be set in the middle of each dedicated 'In-air head.

It had a defect in that its characteristics were inferior to that of a dedicated magnetic head in both recording and reproduction.

To solve this problem, a magnetic head for recording/reproducing with a variable gap has been proposed (Japanese Patent Laid-Open No. 60-68
No. 310, etc.), that is, a magnetic head with a structure in which a magnetic layer with a saturation magnetic flux density lower than that of the head body is inserted in the gap part of the magnetic head, and this magnetic layer is used to withstand the large magnetic flux applied during recording. The magnetic layer is saturated, thereby effectively operating as a magnetic head with a large gap length, and the magnetic flux applied from a recording medium such as a magnetic disk during reproduction does not saturate this magnetic layer, thereby causing a magnetic head with a small gap length. It operates as a head. This variable gap magnetic head is excellent in that it has characteristics equivalent to two magnetic heads dedicated to recording and reproduction.

(Problems with the Prior Art) As shown in FIG. 1, the structure near the gap of the variable gap magnetic head described above includes a main body 1 made of a high permeability magnetic material with a large saturation magnetic flux density, and a main body L in the gap. A high permeability magnetic layer 2 with a small saturation magnetic flux density formed on one of the opposing surfaces, or a high permeability magnetic layer 2, 2 with a small saturation magnetic flux density formed on both sides as shown in FIG. )
The main body 1 is usually made of ferrite-based permalloy (Nl-Fe alloy), ferrite-based sendust (Fe-3I-A1 alloy), ferrite, etc., and the magnetic layer 2.2 is made of It is composed of garnet, etc.

In this way, since the main body and the magnetic layer in the gap portion are made of different materials, it takes a lot of effort to manufacture the magnetic head. Another problem is that because the materials of the main body and the magnetic layer are different, the wear is uneven and wears unevenly, resulting in changes in characteristics and clogging.

(Objective of the Invention) It is an object of the present invention to economically manufacture a magnetic head for both recording and reproducing with a variable gap length.Another object of the present invention is to economically manufacture a magnetic head of this type that does not wear out on one side. The purpose is to provide.

(JI of the invention) The magnetic head of the present invention uses an inexpensive ferrite as the main body, forms a Co-Zr alloy layer with high magnetic permeability and high saturation magnetic flux density on the abutting surfaces of the gap portion, and then coats the surface with a Co-Zr alloy layer of high saturation magnetic flux density. It is characterized by forming a Co--Zr alloy layer with magnetic permeability and low saturation magnetic flux density.

(Summary of Effects) According to the above configuration, since the magnetic layer with high saturation magnetic flux density and the magnetic layer with low saturation magnetic flux density differ only in Co and Zr contents, the celadon magnetic layer can be easily manufactured using the same manufacturing method. The magnetic head can be manufactured more economically, and the cost of the magnetic head can be lowered. Furthermore, since the mechanical properties of the celadon magnetic layer are almost the same, uneven wear of the magnetic head is eliminated.

(Detailed Description of the Invention) According to research conducted by the present inventors, it has been found that by changing the composition of the Co--Zr alloy, a magnetic layer with a high saturation magnetic flux density and a magnetic layer with a low magnetic flux density can be constructed. Such a magnetic layer must have high magnetic permeability during recording and playback, and this magnetic alloy also satisfies this requirement.

Conventional magnetic heads usually use ferrite for the main body, with high transparency in the gap. Permalonite Sendust with a ratio of A is used, but in the present invention, an inexpensive ferrite is used for the main body, and a Co-Zr alloy magnetic layer with high magnetic permeability and high saturation magnetic flux density is formed on at least one surface of the gap part. A Co--Zr alloy magnetic layer having equivalent high magnetic permeability and low saturation magnetic flux density is formed thereon.

These magnetic layers can be manufactured by any method such as a well-known sputtering film forming technique using the portion of the ferrite yoke that will be the abutting surface of the gap portion as a base. However, in the present invention, since the celadon magnetic layer has a very similar composition,
It is advisable to form the celadon magnetic layer using the same method. In the embodiment of the present invention, an RF magnetron sputtering method was used.

The preferred alloy composition is Z for high saturation flux density alloys.
r2. Zr content is 10.1 to 20 at% for alloys with a low saturation magnetic flux density of O to 10 at%. Zr content is less than L0at% or 20
Is it transparent if it exceeds at%? +! ! rate decreases, which is undesirable.
However, in general, it is sufficient that there is a sufficient difference in saturation magnetic flux density between the celadon magnetic layers.

Embodiment FIG. 3 shows the structure of the magnetic head of the present invention, in which Mn-Zn
Zr is applied to the gap surface of the single crystal ferrite yoke 10.
A Co-Zr alloy magnetic layer 11 with a small content is formed,
A Co--Zr alloy magnetic layer 12 with a high Zr content is formed thereon. 5102 gap material is used for the gap portion 13. These magnetic layers are RF magnetrons.

It is formed by the grasshopper method.

A Co-Zr alloy containing CO in an amount of 0.1 to 20 at% of Zr was manufactured, and its magnetic properties were measured. Figure 4 shows the results.

The saturation magnetic flux density decreases linearly with the Zr content. Therefore, Co-Z with as low a Zr content as possible
Using r alloy as magnetic fi11 in Fig. 3, 2Qat%
The magnetic layer 12 is made of a Co-Zr alloy having a Zr content close to
By using the magnetic layer 12 as a variable gap means, the magnetic layer 12 is saturated during recording and has high magnetic permeability during reproduction.

Note that an actual variable gap magnetic head can be configured as follows, for example.

Gap material S+02 0.4 pL
Gap depth 10 IL body M n -Z n single crystal ferrite magnetic layer 11 (high Ms) Co 95at$ 28 gZr
5at! Magnetic layer 12 (low Ms) Co 83atl I
JJ-Z r 17aH (Function and Effect) As described above, 1 the present invention consists of a low saturation magnetic flux density magnetic layer 2 that changes the effective gap made of a Co-Zr alloy with a high Zr content, and a high saturation magnetic flux density magnetic layer. Since the layer 11 is made of a Co--Zr alloy with a low Zr content which is very similar to this, it can be easily manufactured by sputtering by simply changing the target. Furthermore, since the magnetic permeabilities of both magnetic layers exhibit almost the same high values, a magnetic head with good characteristics can be constructed. Furthermore, since the mechanical properties of both magnetic layers are extremely similar, no uneven wear occurs.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views near the gap of a conventional variable gap magnetic head, FIG. 3 is a cross-sectional view of the variable gap magnetic head of the present invention near the gap, and FIG. 4 is a composition of the magnetic layer. It is a graph showing the relationship between magnetic properties and magnetic properties.

Claims (3)

[Claims] (1) Form a Co-Zr alloy first layer with a high saturation magnetic flux density and low Zr content on at least one of the abutting surfaces of the gap part, and then form a Co-Zr alloy first layer with a low saturation magnetic flux density and a higher Zr content than the first layer. A magnetic head characterized in that a second layer of Co--Zr alloy is formed. (2) The magnetic head according to item 1 above, wherein the first layer contains 2.0 to 10.0 at% Zr. (3) The magnetic head according to item 1 or 2 above, wherein the second layer contains 10.1 to 20 at% Zr.